System and method for reconditioning a chiller

ABSTRACT

A system and method for reconditioning a chiller in which moisture has contaminated a refrigerant side of the chiller includes draining refrigerant from the refrigerant side of the chiller and operating a moisture removal assembly connected thereto to remove remaining moisture. The chiller is then recharged with refrigerant and a refrigerant purification assembly connected to the chiller is operated to remove contaminates, such as particulate matter, from the refrigerant. The refrigerant purification assembly includes a vacuum line connected to the chiller for receiving refrigerant drawn out of the chiller and a diaphragm pump connected to the vacuum line and operable to draw refrigerant out of the chiller and through the vacuum line to the pump. A filter assembly is disposed in the vacuum line intermediate the chiller and the pump for filtering contaminates out of refrigerant drawn through the vacuum line.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to chillers, and more particularly to a system and method for reconditioning a chiller that has experienced contamination of the refrigerant side of the chiller.

[0002] Chillers conventionally include a compressor, a condenser, an expansion device and an evaporator with a refrigerant, such as Freon, continuously cycled through the chiller. Refrigerant enters the compressor in a gaseous, low pressure state and is compressed to substantially increase the pressure of the refrigerant gas. High pressure refrigerant gas is then delivered to the condenser where the gas is cooled and condensed to its liquid state by cooling media, such as cooling water, flowing through cooling tubes disposed in the condenser. High pressure refrigerant liquid leaves the condenser and flows through an expansion device to decrease the pressure of the refrigerant liquid. As a result, refrigerant is delivered to the evaporator as a cooled, relatively low pressure liquid. Water to be chilled flows through tubes disposed in the evaporator so that heat exchange takes place between the water to be chilled and the refrigerant liquid in the evaporator. The heat exchange chills the water in the tubes and causes refrigerant liquid to vaporize back to its gaseous state. Low pressure refrigerant gas is then delivered back to the compressor for continuous recycling through the chiller.

[0003] Occasionally, a rupture or leak may occur in the tubes carrying water through the chiller, such as in the condenser or the evaporator carrying. In such an instance, water enters the refrigerant side of the chiller and flows to the various operating components along with the refrigerant. The water is generally unpurified, containing salts and other sediments, and can cause damage to the various operating components of the chiller. For example, water can mix with oil in the compressor and damage the compressor. Water can also cause rusting of the evaporator housing, or particulate matter in the water may coat the heat exchange surfaces (e.g., the water carrying tubes) disposed in the evaporator with residue. The tubes can become so coated with residue that efficient heat exchange between the water in the tubes and the refrigerant in the evaporator is inhibited. However, the areas around and between the tubes are inaccessible for mechanical cleaning and drying. Consequently, replacement of the tubes, or even the entire chiller, may be required.

[0004] To recondition a chiller after such a leak or rupture occurs, the chiller is shut down and the contaminated refrigerant is typically drained from the chiller in an effort to dry out the chiller. A vacuum pump is then connected to the chiller, such as at the evaporator, to suction out any moisture remaining in the chiller. Subjecting the air in the chiller to a vacuum causes the boiling point of water remaining in the chiller to substantially decrease. As a result, the water vaporizes, making it easier to draw moisture out of the chiller. However, water vapor drawn into the vacuum pump tends to mix with the vacuum pump oil rather rapidly, requiring a service technician to change the oil frequently (e.g., daily) to avoid damage to the pump. The frequent need for oil changes substantially slows the moisture removal effort, often requiring a month or more to dry out the chiller, and even then such efforts are not always successful at fully reconditioning the chiller.

SUMMARY OF THE INVENTION

[0005] Among the several objects and features of the present invention may be noted the provision of a system and method for reconditioning a chiller which facilitates reconditioning of the chiller after a rupture or leak occurs in which water enters the refrigerant side of the chiller; the provision of such a system and method which facilitates the removal of moisture from the refrigerant side of the chiller; the provision of such a system and method which facilitates the removal of contaminates from the refrigerant side of the chiller; the provision of such a system and method which is at least partially carried out during operation of the chiller; and the provision of such a system and method which is efficient and cost effective.

[0006] In general, a system of the present invention for reconditioning a chiller in which moisture has contaminated a refrigerant side of the chiller comprises a moisture removal assembly adapted for connection to the chiller in fluid communication with the refrigerant side of the chiller after the chiller has been drained of refrigerant. The moisture removal assembly is operable to remove moisture remaining in the chiller after the chiller has been drained. A refrigerant purification assembly is adapted for connection to the chiller in fluid communication with the refrigerant side of the chiller after the chiller has been recharged with refrigerant following the removal of moisture from the refrigerant side of the chiller. The refrigerant purification assembly comprises a vacuum line connected to the chiller for receiving refrigerant drawn out of the chiller. A diaphragm pump is connected to the vacuum line for fluid communication with the chiller. The diaphragm pump is operable to draw refrigerant out of the chiller and through the vacuum line to the pump. A filter assembly is disposed in the vacuum line intermediate the chiller and the pump for filtering contaminates out of refrigerant drawn from the chiller through the vacuum line. A discharge line is connected to the pump for receiving filtered refrigerant discharged from the pump.

[0007] A refrigerant purification assembly of the present invention for removing particulate matter from a refrigerant side of a chiller generally comprises a vacuum line connected to the chiller for receiving refrigerant drawn out of the chiller. A diaphragm pump is connected to the vacuum line for fluid communication with the chiller and is operable to draw refrigerant out of the chiller and through the vacuum line to the pump. A filter assembly is disposed in the vacuum line intermediate the chiller and the diaphragm pump for filtering contaminates out of refrigerant drawn from the chiller through the vacuum line. A discharge line is connected to the pump for receiving filtered refrigerant discharged from the diaphragm pump.

[0008] A moisture removal assembly of the present invention for removing moisture from a refrigerant side of a chiller after refrigerant has been drained from the chiller generally comprises a vacuum pump in fluid communication with the refrigerant side of the chiller for drawing air and moisture out of the chiller. A cold trap is disposed intermediate the chiller and the pump for condensing and collecting moisture therein to inhibit moisture from being drawn into the vacuum pump.

[0009] A method of the present invention for reconditioning a chiller following an event in which water enters a refrigerant side of the chiller generally comprises draining refrigerant from the refrigerant side of the chiller and removing moisture remaining in the chiller after draining refrigerant from the refrigerant side of the chiller. The chiller is then recharged with refrigerant. Contaminates are removed from the chiller after the chiller has been recharged with refrigerant by drawing refrigerant out of the chiller and directing the refrigerant to flow through a filter assembly to remove contaminates from the refrigerant. Refrigerant is drawn out of the chiller by operating a diaphragm pump in fluid communication with the refrigerant side of the chiller to draw refrigerant out of the chiller and through a vacuum line to the diaphragm pump. The filter assembly is disposed in the vacuum line so that refrigerant drawn from the chiller through the vacuum line flows through the filter assembly before being drawn into the diaphragm pump.

[0010] In another embodiment, a method of the present invention of removing contaminates from a refrigerant side of a chiller generally comprises connecting a diaphragm pump to the chiller in fluid communication with the refrigerant side of the chiller and operating the diaphragm pump to draw refrigerant out of the chiller to flow to the diaphragm pump. Refrigerant drawn out of the chiller is directed to flow through a filter assembly to remove contaminates from the refrigerant before the refrigerant is drawn into the pump.

[0011] Finally, a method of the present invention of removing moisture remaining in a chiller after refrigerant has been drained from a refrigerant side of the chiller generally comprises connecting a moisture removal assembly to the chiller in fluid communication with the refrigerant side of the chiller after refrigerant has been drained from the refrigerant side of the chiller. The moisture removal assembly comprises a vacuum pump and a cold trap intermediate the chiller and the vacuum pump. The vacuum pump is operated to draw moisture and air from the refrigerant side of chiller into the cold trap whereby moisture condenses and accumulates in the cold trap to inhibit moisture against being drawn into the vacuum pump.

[0012] Other objects and features of the present invention will be in part apparent and in part pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is a schematic illustration of a conventional chiller with a system of the present invention for reconditioning a chiller connected thereto;

[0014]FIG. 2 is a schematic illustration of a moisture removal assembly of the system of FIG. 1 for reconditioning a chiller; and

[0015]FIG. 3 is a plan view of a refrigerant purification assembly of the system of FIG. 1 for reconditioning a chiller.

[0016] Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0017] Referring now to the drawings and in particular to FIG. 1 a conventional chiller is schematically illustrated and generally designated in its entirety by the reference numeral 21. The chiller includes a compressor 23, a condenser 25, an expansion device, such as an expansion valve 27, and an evaporator 29. These operating components are serially connected in fluid communication with each other to direct a refrigerant 31 such as Freon through the chiller in a continuous, cyclical manner as shown in FIG. 1 by the directional arrows. Cooling tubes 33 extend through the condenser 25 and are connected to an external source (not shown) of cooling water for directing cooling water to flow through the tubes. Another set of tubes 35 extends through the evaporator 35 and is connected to an independent source (not shown) of water to be chilled (e.g., separate from the source of cooling water).

[0018] During cyclical operation of the chiller 21, refrigerant 31 enters the compressor 23 in a gaseous, low pressure state and is compressed to substantially increase the gas pressure of the refrigerant. High pressure refrigerant gas is then delivered to the condenser 25 where the refrigerant gas is cooled and condensed to its liquid state as a result of heat transfer with cooling water flowing through the cooling tubes 33 disposed in the condenser. High pressure refrigerant liquid is directed out of the condenser 25 and flows through the expansion valve 27 to decrease the pressure of the refrigerant liquid. As a result, refrigerant 31 is delivered to the evaporator 29 in a cooled, relatively low pressure liquid state. Water to be chilled by the chiller 21 flows through the tubes 35 in the evaporator 29 to effect heat exchange between the water to be chilled and the refrigerant liquid in the evaporator. This heat exchange chills the water in the tubes 35 and causes refrigerant liquid to vaporize to its low pressure, gaseous state. Low pressure refrigerant gas is then delivered back to the compressor 23 for continuous recycling through the chiller 21.

[0019] Construction and operation of the chiller 21 described above, including construction and operation of each of the various operating components of the chiller, is known to those skilled in the art. Further construction and operation of the chiller 21 will therefore not be described herein except to the extent necessary to disclose the present invention.

[0020] When a rupture or leak occurs in one or more of the tubes 33, 35 carrying water through the chiller 21, such as in the condenser 25 or the evaporator 29, water enters the refrigerant side of the chiller and cycles through the various operating components of the chiller along with the refrigerant 31. Moisture in the refrigerant side of the chiller 21 can damage the chiller and result in failure of one or more of its various operating components. Therefore, it is necessary to remove moisture from the refrigerant side of the chiller 21 as quickly as possible and to further remove any particulate matter formed in the chiller as a result of salts or other sediments present in the water entering the refrigerant side of the chiller.

[0021] Still referring to FIG. 1, a system of the present invention for reconditioning the chiller 21 after moisture enters the refrigerant side of the chiller is generally indicated at 51. The reconditioning system 51 comprises a moisture removal assembly, generally indicated at 101 in FIG. 2, for removing moisture from the chiller 21 and a refrigerant purification assembly, generally indicated at 201 in FIG. 3, for removing particulate matter from the chiller.

[0022] As shown in FIG. 2, the moisture removal assembly 101 includes a vacuum pump 103 for drawing moisture and air from the chiller 21 and a cold trap, generally indicated at 105, intermediate the vacuum pump and the chiller for inhibiting moisture against being drawn into the pump. The cold trap 105 of the illustrated embodiment comprises a vessel 107 having an interior chamber 109 and having an inlet 111 for receiving air and moisture from the chiller 21 into the chamber. A suitable inlet line 113 is connected at one end to the vessel 107 at the inlet 111 and at its other end to the evaporator 29 to provide fluid communication between the refrigerant side of the chiller 21 and the cold trap chamber 109. An outlet line 115 is connected at one end to the vessel 107 at an outlet 117 of the housing and is connected at its other end to the vacuum pump 103 to provide fluid communication between the vacuum pump and the cold trap chamber 109 such that operation of the vacuum pump draws air and moisture from the chiller 21 through the cold trap chamber to the vacuum pump. A solenoid valve 119 is disposed in the inlet line 113 and is operable between an open position in which air and moisture from the chiller 21 may be drawn into the cold trap chamber 109 and a closed position in which the inlet line is sealed against air and moisture being drawn into the chamber.

[0023] A cooling coil 121 is positioned in the cold trap chamber 109 and is connected via an inlet line 123 to a source of low temperature fluid, such as chilled water, Freon or brine, for cycling low temperature fluid through the cooling coil to an outlet line 125. A drain opening 127 is disposed in the bottom of the vessel 107 for draining water from the chamber 109 and the top of the housing has an air vent 129 for venting the chamber 109 as water is drained from the chamber. A solenoid valve 131 is located in a drain line 133 leading from the drain opening 127 and is operable between an open position in which water can be drained from the chamber 109 and a closed position in which the chamber is sealed against water drainage. Another solenoid valve 135 is positioned in an exhaust line 137 leading from the air vent 129 and is operable in conjunction with the solenoid valve 131 in the drain line 133 to vent the chamber 109 to atmosphere as water is being drained from the chamber. A float switch 139 is electrically connected to the solenoid valves 119, 131, 135 of the cold trap 105 to control operation of the valves. The float switch 139 may also be electrically connected to the vacuum pump 103 for shutting down the vacuum pump as water is drained from the chamber 109.

[0024] In operation, with the refrigerant side of the chiller 21 drained of refrigerant 31, the moisture removal assembly 101 is connected to the chiller, such as by connecting the inlet line 113 of the cold trap 105 to the evaporator 29, to provide fluid communication between the moisture removal assembly and the refrigerant side of the chiller. Since no water is in the bottom of the cold trap chamber 109, the float switch 139 is in an off position wherein the solenoid valve 119 in the inlet line 113 is in its open position and the solenoid valves 131, 135 in the drain line 133 and exhaust line 137 are in their closed position. The vacuum pump 103 is operated to draw a vacuum on the interior of the chiller 21. The decreased pressure in the chiller 21 causes the boiling point of water remaining therein to decrease substantially, resulting in vaporization of the water. Air and water vapor are thus drawn from the chiller 21 through the inlet line 113 and into the cold trap chamber 109 where the water vapor condenses on the cooling coil 121 while air is drawn through the outlet line 115 to the vacuum pump 103. Water drips off the cooling coil 121 and accumulates at the bottom of the chamber 109 until the float switch 139 is moved to its on position. In the on position of the float switch 139, the solenoid valve 119 in the inlet line 113 is moved to its closed position and the solenoid valves 131, 135 in the drain line 133 and the exhaust line 137 are opened for draining water from the bottom of the cold trap chamber 109 until the float switch 139 returns to its off position. The vacuum pump 103 may either remain operational or it may be shut down while water is drained from the chamber 109, as long as the solenoid valve 135 in the exhaust line 137 is in its open position.

[0025] Now referring to FIG. 3, the refrigerant purification assembly 201 includes a vacuum line 203 connected at one end to the evaporator 29, such as by being welded thereto, for receiving refrigerant liquid from the evaporator into the purification assembly. The vacuum line 203 of the illustrated embodiment leads to the evaporator 29 for connection thereto generally at the bottom of the evaporator. However, the vacuum line 203 may be connected to the evaporator 29 other than at the bottom of the evaporator as long as the connection is below the liquid level of refrigerant 31 in the evaporator. The other end of the vacuum line 203 is connected to a pump 205 to provide fluid communication between the pump and the evaporator 29 for drawing refrigerant liquid from the chiller 21 through the refrigerant purification assembly 201.

[0026] A filter assembly, generally indicated at 207, is positioned in the vacuum line 203 intermediate the evaporator 29 and the pump 205 so that refrigerant 31 drawn from the evaporator into the assembly 201 flows through the filter assembly before being drawn into the pump. The filter assembly 207 includes a filter housing 209 and one or more filter elements (not shown) disposed in the filter housing for filtering contaminates, such as particulate matter, from the refrigerant 31 as the refrigerant is drawn through the purification assembly 201. The filter housing 209 of the illustrated embodiment is sized to contain four gallons of refrigerant 31 and houses four individual filter elements. One preferred filter housing 209 is manufactured by Sporlan Valve Co. of Washington, Missouri under model designation C-40017-G. A preferred filter element is also commercially available from Sporlan Valve Co. under model designation RPE-100.

[0027] While the filter assembly 207 of the illustrated embodiment houses a filter element for filtering particulate matter from the refrigerant drawn through the purification assembly 201, it is understood that filter elements for filtering other contaminates, such as acid or moisture, from the refrigerant may be used instead of, or in conjunction with, a filter element for filtering particulate matter from the refrigerant without departing from the scope of this invention.

[0028] An isolation valve 211 is disposed in the vacuum line 203 upstream of the filter housing 209 and is in an open position of the valve during operation of the purification assembly 201 to permit the flow of refrigerant from the evaporator 29. The isolation valve 211 is manually movable to a closed position to seal the chiller from the refrigerant purification assembly 201 when the assembly is inoperative, such as when the filter elements need to be replaced or the pump 205 requires servicing. Another isolation valve 213 is disposed in the vacuum line 203 between the filter housing 209 and the pump 205. This second isolation valve 213 is open when the refrigerant purification assembly 201 is operating, and is manually movable to a closed position for isolating the filter housing 209 (along with the first isolation valve 211) from both the chiller 21 and the pump 205 when the filter elements need replacing.

[0029] The pump 205 of the illustrated embodiment is a diaphragm pump. Diaphragm pumps are known to those skilled in the art as being particularly resistant to damage and operating inefficiencies caused by cavitation. One preferred diaphragm pump 205 is an air operated pump commercially available from Wilden Pump and Engineering Co. of Grand Terrace, Calif. under model designation P4 BOLTED SERIES ALUMINUM PUMP. The diaphragms (not shown) used in the pump 205 are elastomeric and are preferably chemically compatible with the refrigerant 31 being drawn through the pump. As an example, the diaphragms used in the pump 205 of the illustrated embodiment are constructed of a material commercially available from E. I. Du Pont de Nemours and Company under the tradename NORDEL. Other internal pump components (not shown) that come into contact with the refrigerant 31 are also preferably chemically compatible with the refrigerant.

[0030] The pump 205 is connected to a source (not shown) of compressed air by a suitable air line 215, and an exhaust line 217 leads from the pump for exhausting air therefrom. A manual shut-off valve 219 in the air line 215 is movable between an open position in which pressurized air is permitted to flow to the pump 205 for pneumatically operating the pump and a closed position in which air is sealed against flowing to the pump, such as when servicing of the pump is required. A conventional combination air filter and pressure regulator, generally indicated at 221, is disposed in the air line 215 downstream of the shut-off valve 219. A pressure gauge 223 is also positioned in the air line 215 leading to the pump 205. A muffler 225 is positioned at the outer end of the air exhaust line 217. Air flow through assembly 201 is controlled automatically by a solenoid valve 227 disposed in the air line 215 upstream of the pump 205 and another solenoid valve 229 disposed in the exhaust line 217 downstream of the pump. The valves 227, 229 are operable conjointly between an open position in which both valves are open to permit operation of the pump 205 and a closed position in which the valves are closed to seal against the loss of refrigerant from the pump through the air line 215 and exhaust line 217 in the event that a diaphragm ruptures within the pump. The solenoid valves 227, 229 may also be electrically connected to the chiller control system (not shown) so that the valves are moved automatically to their closed position when the chiller 21 is shut down for any reason to thereby shut down operation of the refrigerant purification assembly 201.

[0031] A discharge line 231 is connected to the pump 205 for carrying filtered refrigerant liquid discharged from the pump. The discharge line 231 of the illustrated embodiment is connected to the evaporator 29, such as by being welded thereto, generally toward the bottom of the evaporator (e.g., below the liquid level of refrigerant in the evaporator) so that filtered refrigerant liquid is pumped back into the chiller. As an example, the refrigerant purification assembly 201 of the illustrated embodiment is capable of cycling up to forty gallons of refrigerant per minute from a chiller 21 charged with approximately 1400 pounds of refrigerant. As a result, all of the refrigerant 31 in the chiller 21 can be cycled through the refrigerant purification assembly 201 approximately once every 3-5 minutes. However, it is contemplated that the discharge line 231 may instead be free from connection with the chiller 21, such that filtered refrigerant is discharged into a collection tank (not shown) separate from the chiller 21 for inspection or further processing without departing from the scope of this invention.

[0032] An isolation valve 233 is disposed in the discharge line 231 downstream of the pump 205 and is in an open position during operation of the assembly 201 to permit refrigerant discharged from the pump to be delivered back into the evaporator 29.

[0033] When the assembly 201 is inoperable, such as during servicing of the chiller 21 or the assembly, the valve 233 may be manually moved to a closed position to isolate the assembly from the chiller along with the valve 211 in the vacuum line 203 for sealing the assembly against refrigerant from the chiller flowing backward through the discharge line 231 to the pump 205. Another pressure gauge 235 is positioned in the discharge line 231 intermediate the pump 205 and the isolation valve 233.

[0034] The reconditioning system 51 of the present invention is schematically illustrated in FIG. 1 as a single unit connected to the evaporator 29 of the chiller 21. It is understood, however, that the moisture removal assembly 101 and the refrigerant purification assembly 201 are separately connected to the chiller 21, and that the moisture removal assembly 101 and refrigerant purification assembly 201 may be connected to the evaporator 29, or to other components of the chiller, and may be connected simultaneously to the chiller or only one of the assemblies 101, 201 may be connected to the chiller without departing from the scope of this invention.

[0035] The reconditioning system 51 is preferably used by a technician in accordance with a method of the present invention for reconditioning the chiller 21. First, the chiller 21 is shut down and the refrigerant side of the chiller is drained to remove contaminated refrigerant 31 from the chiller. The moisture removal assembly 101 is then connected to the chiller 21, such as by connecting the inlet line 113 of the cold trap 105 to the evaporator 29, to provide fluid communication between the vacuum pump 103 of the assembly and the refrigerant side of the chiller. The moisture removal assembly 101 is operated as discussed previously to remove moisture remaining in the chiller 21 after draining the contaminated refrigerant 31. Once moisture is removed from the chiller 21, the refrigerant side of the chiller is recharged with uncontaminated refrigerant 31 and operation of the chiller is resumed. Operation of the chiller 21 tends to break loose rust and residue present in the refrigerant side of the chiller. While the chiller 21 is operating, the refrigerant purification assembly 201 is operated to cycle refrigerant 31 through the filter assembly 207 to remove particulate matter from the refrigerant. It is understood, however, that the refrigerant purification assembly 201 may instead be operated while the chiller 21 is inoperable without departing from the scope of this invention.

[0036] Also, while the refrigerant purification assembly 201 is disclosed herein as being used in the event that a rupture or leak in the chiller 21 results in water entering the refrigerant side of the chiller, it is understood that the refrigerant purification assembly may be run at all times during operation of the chiller to remove contaminates present in the refrigerant of the chiller.

[0037] In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.

[0038] When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.

[0039] As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. 

What is claimed is:
 1. A system for reconditioning a chiller in which moisture has contaminated a refrigerant side of the chiller, the chiller being of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the system comprising: a moisture removal assembly adapted for connection to the chiller in fluid communication with the refrigerant side of the chiller after the chiller has been drained of refrigerant, the moisture removal assembly being operable to remove moisture remaining in the chiller after the chiller has been drained; and a refrigerant purification assembly adapted for connection to the chiller in fluid communication with the refrigerant side of the chiller after the chiller has been recharged with refrigerant following the removal of moisture from the refrigerant side of the chiller, the refrigerant purification assembly comprising a vacuum line connected to the chiller for receiving refrigerant drawn out of the chiller, a diaphragm pump connected to the vacuum line for fluid communication with the chiller, the diaphragm pump being operable to draw refrigerant out of the chiller and through the vacuum line to the pump, a filter assembly disposed in the vacuum line intermediate the chiller and the pump for filtering contaminates out of refrigerant drawn from the chiller through the vacuum line, and a discharge line connected to the pump for receiving filtered refrigerant discharged from the pump.
 2. A system as set forth in claim 1 wherein the vacuum line of the refrigerant purification assembly is connected to the evaporator of the chiller generally below the liquid level of refrigerant in the evaporator.
 3. A system as set forth in claim 1 wherein the discharge line of the refrigerant purification assembly is further connected to the chiller for delivering filtered refrigerant discharged from the diaphragm pump back into the chiller.
 4. A system as set forth in claim 3 wherein the discharge line of the refrigerant purification assembly is connected to the evaporator of the chiller generally below the liquid level of the refrigerant in the evaporator.
 5. A system as set forth in claim 1 wherein the moisture removal assembly comprises a vacuum pump in fluid communication with the refrigerant side of the chiller for drawing air and moisture out of the chiller and a cold trap intermediate the chiller and the pump for condensing and collecting moisture therein to inhibit moisture from being drawn into the vacuum pump.
 6. A refrigerant purification assembly for removing particulate matter from a refrigerant side of a chiller of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the refrigerant purification assembly comprising: a vacuum line connected to the chiller for receiving refrigerant drawn out of the chiller, a diaphragm pump connected to the vacuum line for fluid communication with the chiller, the diaphragm pump being operable to draw refrigerant out of the chiller and through the vacuum line to the pump; a filter assembly disposed in the vacuum line intermediate the chiller and the diaphragm pump for filtering contaminates out of refrigerant drawn from the chiller through the vacuum line; and a discharge line connected to the pump for receiving filtered refrigerant discharged from the diaphragm pump.
 7. A refrigerant purification assembly as set forth in claim 6 wherein the vacuum line is connected to the evaporator of the chiller generally below the liquid level of refrigerant in the evaporator.
 8. A refrigerant purification assembly as set forth in claim 6 wherein the discharge line is further connected to the chiller for delivering filtered refrigerant discharged from the diaphragm pump back into the chiller.
 9. A refrigerant purification assembly as set forth in claim 8 wherein the discharge line is connected to the evaporator of the chiller generally below the liquid level of the refrigerant in the evaporator.
 10. A refrigerant purification assembly as set forth in claim 8 further comprising an isolation valve disposed in the vacuum line upstream of the filter assembly and being open during operation of the refrigerant purification assembly, and another isolation valve disposed in the discharge line and being open during operation of the refrigerant purification assembly, the isolation valves each being movable to a closed position when the refrigerant purification assembly is inoperable to isolate the refrigerant purification assembly from the refrigerant side of the chiller.
 11. A refrigerant purification assembly as set forth in claim 6 wherein the refrigerant purification assembly is operable concurrently with operation of the chiller.
 12. A refrigerant purification assembly as set forth in claim 11 wherein operation of the refrigerant purification assembly is responsive to operation of the chiller whereby shutting down the chiller causes the refrigerant purification assembly to shut down.
 13. A moisture removal assembly for removing moisture from a refrigerant side of a chiller after refrigerant has been drained from the chiller, the chiller being of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the moisture removal assembly comprising a vacuum pump in fluid communication with the refrigerant side of the chiller for drawing air and moisture out of the chiller and a cold trap intermediate the chiller and the pump for condensing and collecting moisture therein to inhibit moisture from being drawn into the vacuum pump
 14. A method of reconditioning a chiller following an event in which water enters a refrigerant side of the chiller, the chiller being of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the method comprising the steps of: draining refrigerant from the refrigerant side of the chiller; removing moisture remaining in the chiller after draining refrigerant from the refrigerant side of the chiller; recharging the chiller with refrigerant; and removing contaminates from the chiller after the chiller has been recharged with refrigerant, the step of removing contaminates from the chiller comprising drawing refrigerant out of the chiller and directing the refrigerant to flow through a filter assembly to remove contaminates from the refrigerant, the step of drawing refrigerant out of the chiller comprising operating a diaphragm pump in fluid communication with the refrigerant side of the chiller to draw refrigerant out of the chiller and through a vacuum line to the diaphragm pump, the filter assembly being disposed in the vacuum line so that refrigerant drawn from the chiller through the vacuum line flows through the filter assembly before being drawn into the diaphragm pump.
 15. A method as set forth in claim 14 further comprising directing filtered refrigerant discharged from the diaphragm pump to flow back into the chiller.
 16. A method as set forth in claim 14 wherein the step of removing contaminates from the chiller is performed during operation of the chiller.
 17. A method as set forth in claim 14 wherein the step of removing moisture remaining in the chiller after draining refrigerant from the refrigerant side of the chiller comprises: connecting a moisture removal assembly to the chiller in fluid communication with the refrigerant side of the chiller; and operating the moisture removal assembly to draw moisture and air from the refrigerant side of the chiller.
 18. A method as set forth in claim 17 wherein the moisture removal assembly comprises a vacuum pump and a cold trap intermediate the chiller and the vacuum pump, the step of operating the moisture removal assembly to draw moisture and air from the refrigerant side of the chiller comprising operating the vacuum pump to draw moisture and air from the refrigerant side of chiller into the cold trap whereby moisture condenses and accumulates in the cold trap to inhibit moisture against being drawn into the vacuum pump.
 19. A method of removing contaminates from a refrigerant side of a chiller, the chiller being of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the method comprising the steps of: connecting a diaphragm pump to the chiller in fluid communication with the refrigerant side of the chiller; operating the diaphragm pump to draw refrigerant out of the chiller to flow to the diaphragm pump; and directing refrigerant drawn out of the chiller to flow through a filter assembly to remove contaminates from the refrigerant before the refrigerant is drawn into the pump.
 20. A method as set forth in claim 19 comprising directing filtered refrigerant discharged from the diaphragm pump to flow back into the chiller.
 21. A method as set forth in claim 19 wherein the diaphragm pump is operated to draw refrigerant from the chiller during operation of the chiller.
 22. A method as set forth in claim 19 wherein the contaminates filtered from the refrigerant by the filter assembly comprise particulate matter.
 23. A method of removing moisture remaining in a chiller after refrigerant has been drained from a refrigerant side of the chiller, the chiller being of the type having a condenser, a compressor, an expansion device, an evaporator and a refrigerant continuously cycled through the refrigerant side of the chiller, the method comprising the steps of: connecting a moisture removal assembly to the chiller in fluid communication with the refrigerant side of the chiller after refrigerant has been drained from the refrigerant side of the chiller, the moisture removal assembly comprising a vacuum pump and a cold trap intermediate the chiller and the vacuum pump; and operating the vacuum pump to draw moisture and air from the refrigerant side of chiller into the cold trap whereby moisture condenses and accumulates in the cold trap to inhibit moisture against being drawn into the vacuum pump. 